Marked thrombocytosis during treatment with ceftazidime for pulmonary infection.

When an infected patient suffers from thrombocytosis, it is very difficult to identify beta-lactam antibiotic induced cases of the disease and separate these from the possibility that the disease is an acute-phase reaction in the infected patient. We present the case of a 54-year-old man who was treated with ceftazidime for pneumonia and developed thrombocytosis during the treatment course. Thrombocytosis persisted until ceftazidime was discontinued, despite clinical and radiological evidence showing that the pneumonia had greatly improved. The Naranjo probability scale indicates ceftazidime as the possible cause of the thrombocytosis in our patient. Although no obvious complications occur in most patients, we should pay close attention to the possibility of adverse reactions and evaluate whether the infection is treated with the appropriate antibiotics.